In IEEE 802.11 (Wireless LAN), MAC Management is responsible for controlling and managing how devices communicate and stay connected within the network.
The key responsibilities of MAC Management include: synchronization, power management, association/reassociation, and maintaining the MAC Management Information Base (MAC MIB).
1. Synchronization
- In a wireless LAN, all stations (devices) must stay synchronized to ensure proper communication.
- Access Points (APs) send out beacon frames at regular intervals.
- These beacons contain timing information that helps stations adjust their clocks and maintain timing alignment.
- This is crucial for timing operations like sleep/wake cycles in power-saving modes.
2. Power Management
- Allows devices to conserve battery by entering low-power (sleep) mode when not transmitting or receiving.
- Stations can inform the AP when they enter power-saving mode.
- During this time, the AP buffers any incoming data for the sleeping device.
- Devices periodically wake up to check for buffered data (via beacon frames).
3. Association / Reassociation
- Association: The process where a station connects to an AP to gain access to the network.
- Involves exchanging association request/response frames.
- The AP assigns an Association ID (AID) to the station.
- Reassociation: Happens when a mobile station moves from one AP’s range to another.
- Ensures seamless handoff and continuous connectivity (important for roaming).
4. MAC Management Information Base (MAC MIB)
- It is a database of parameters and status information maintained by each station or AP.
- Contains:
- Configuration settings (SSID, supported rates, etc.)
- Current state (associated, authenticated, etc.)
- Performance data (packet counts, error rates, etc.)
- Used by network management systems to monitor and control wireless communication effectively.